I don't mean this as a comment in particular against this man, but whenever I see explications of tai chi like this, there is always one thing that strikes me as, well, just odd: the treatment of the spine as a stick that just rotates axially, and the translation of the torso in space as only that vertically bricked unit.

When he does that one karate stance to show how he can't take the push, and then when he "splits", you can see that his torso is still being levered precariously. All of the strain is essentially being focused into his hip and stomach muscles to bridge the harsh change in direction between his leg and his torso, rather than uniformly distributed throughout every joint in his body.

There is a much easier and stupid simpler way to take that push down: arc the spine into a curved bridge that takes that it down and minimizes leverage at every single point in the body, you just allow the spine to flex into that bridge. No "split" necessary. You could combine that with the splitting to make it even more powerful, but the split doesn't have to be the primary means by which it is done, no?

But, well, I never see this in most tai chi. It is probably just a limitation of my present understanding, but still, this always strikes me as odd.